As multi-purpose wireless devices become too small for standard mechanical/electronic keyboards, virtual keyboards are increasing being used as a primary input device by displaying an arrangement of keys on a touchscreen. The user enters a keystroke by simply touching the screen with a fingertip at the location where the desired key is displayed. Because of the small size and hand-held nature of these devices, many users typically use only their thumbs to enter the data. However, most of these virtual keyboards arrange the keys in either a rectangular matrix of keys, or in the standard QWERTY format. The linear nature of the rows in such arrangements makes them ill suited for used by the thumbs. Specifically, to move his thumb along the length of a row of keys or along the height of a column of keys, a user must articulate the several joints of his thumb in a relatively unnatural manner. Indeed, becoming accustomed to such arrangements can require extensive proprioceptive development from the user. While the designs of some physical keyboards on multi-purpose wireless devices do provide improved ergonomics (compared to a rectangular matrix of keys), the degree of to which the ergonomics can be tailored to a particular individual remains limited. Further, such designs do not account for the fact different users have different sizes of hands, fingers and thumbs, so a keyboard that is properly sized for one user may be more difficult for another user.